In order to guard against forgeries or falsifications and to increase the level of security, it is known to use security elements applied at the surface or introduced in the bulk or as window(s) in a security article, especially a security document, or other object, for example a label, packaging, especially for medicines, foods, cosmetics, electronic parts or spare parts.
The security article can especially be chosen from among a payment means, such as a banknote, a restaurant voucher or ticket, an identity document such as an identity card, a visa, a passport or a driver's license, a lottery ticket, a transport pass or else an entry ticket for shows.
The exposure of images animated by a parallax effect has been known for a great many years.
Several patents relying on this principle have been filed, for example U.S. Pat. No. 5,098,302, U.S. Pat. No. 5,525,383 and U.S. Pat. No. 6,286,873.
Methods are known for creating illusions of motion such as are described in the documents U.S. Pat. No. 5,901,484 and U.S. Pat. No. 6,286,873 using a carrier support bearing several coded images, corresponding for example to the decomposition of the motion of an object or of an animal, and a carrier transparent film bearing an array of parallel lines, placed on the support. A relative motion between the coded images and the array of parallel lines makes it possible to create the illusion of a motion.
U.S. Pat. No. 6,286,873 teaches the possibility of observing coded images on each side of an optical system comprising an exposure screen and a combined image, situated on either side of a substrate. This document does not disclose a security element.
Furthermore, diverse other optical systems are known through the publications U.S. Pat. No. 3,241,429, U.S. Pat. No. 3,154,872, U.S. Pat. No. 4,645,301, U.S. Pat. No. 4,892,336, WO 94/27254, U.S. Pat. No. 6,856,462, US 2005/184504, U.S. Pat. No. 5,708,871, WO 2005/052650, WO 2005/058610, US 2005/150964 and WO 2007/020048.
It is known to produce security elements with lenticular arrays associated with specific prints, so as to produce motion effects. The company SECURENCY markets some under the MOTION® brand.
US 2007/0279697 discloses a security element comprising an optical system making it possible to produce a moiré pattern effect.